Apparatus for stretching sheet material



Aug. 11, 1936.

A.G,BORNTRAEGER APPARATUS FOR STRETGHING SHEET MATERIAL Filed Oct; 1, 1954 2 Sheets-Sheet l .l l l l ABEORNTRAEINQIZOR AITIHUWEY Aug. 11, 1936. A. G. BORNTRAEGER 27,050,419

APPARATUS FOR STRETCHING SHEET MATERIAL Filed Oct. 1, 1934 2 Sheets-Sheet 2 Wi I13 E7 14 1 I H I 30 '1 m A G BORNTRAEGER- .WW 7 19 INVENTOR BY 6 ATTORNEY-- Patented Aug. 11, 1936 UNITED STATES PATENT OFFIQE APPARATUS FOR STRETCHING SHEET MATERIAL Application October 1, 1934, Serial No. 746,344

8 Claims.

This invention relates to improvements in apparatus for stretching sheet material and while adapted for use generally wherever it may be advantageously employed, it is particularly intended for application to curtain stretching frames, in which connection it is illustrated in the drawings and hereinafter specifically described.

Objects of the invention are to provide a frame of simple, durable construction which may be quickly and conveniently adjusted and efficiently used to stretch or hold in a normal condition, curtains or other flat, flexible articles of different sizes.

Other objects are to provide a curtain stretching frame having a horizontally movable, vertical curtain engaging bar and a vertically movable, horizontal curtain engaging bar mounted with each end of each bar secured to an endless, flexible belt arranged to maintain said bars at right angles to each other and at right angles to the adjacent side frame member and to thereby provide a frame which may be quickly adjusted to receive rectangular curtains of any reasonable Width and length and which will uniformly hold the same in rectangular form during the stretching operation.

An additional object is to provide a curtain stretcher of the type above indicated which is composed of separable parts adapted to be quickly and conveniently assembled to form a strong, rigid structure and which can be quickly taken apart for shipment or storage.

An illustrative embodiment of the invention is shown in the drawings and hereinafter specifically described, it being understood that the invention is not limited to the exact form shown and that changes and modifications maybe made which come within the spirit of the invention as set forth in the appended claims.

In the drawings:

Figure 1 is a front, elevational view of a curtain stretching frame constructed in accordance with this invention,

Figure 2 is a rear elevational view of same,

Figure 3 is a vertical, sectional View taken as indicated by the lines 33 of Figure 2,

Figure 4 is a horizontal, sectional view taken as indicated by the lines 4-4 of Figure 2.

Figure 5 is a diagrammatic view illustrating a modified form of mounting the movable curtain engaging bars.

Figure 6 is a sectional View taken as indicated by the lines 6& of Figure 1.

Proceeding now to a detailed description of the of which is positioned at each corner of the 10 U frame. The corner member M is L-shaped and is compose-d of sheet metal or other suitable material stamped or otherwise formed with forwardly projecting side walls Ma, Mb, Me and Md forming channels for receiving the abutting end portions of the rails I0, ll, I2 and I3.

The side walls Ma and Mb extend along the outer edges of each corner member M and meet at the outer corner thereof. The walls Mo and Md are disposed along the inner edge of the corner member M terminating at the edge of a web II which extends across the angle of the L to form a support for the sheaves hereinafter described.

The numeral Me denotes a flange which pro- 5 jects inwardly from the upper edge of each side wall Ma. The numeral M denotes a similar flange which projects inwardly from the upper edge of the wall Mb. The inner wall Me is provided at the forward edge thereof with an outwardly disposed flange Mn and the wall Md with an annular flange Mg. The flanges Mf, Mg, I ML and Me are disposed in parallel relation to the main body of the corner member M and serve to retain the frame members III, II, l2 and I3 in assembled relation.

The numeral l9 denotes a, pin which is secured to the web I! so as to project rearwardly therefrom at a right angle to the rear face of each corner member M. Each pin I9 is provided with two sheaves 20 and 2| which are operatively mounted thereon.

In assembling the frame, the ends of the rails H], H, I2 and !3 are positioned in the channels of the members M as illustrated in Figures 1 and 2. The corner members M provide eflicient means for quickly and conveniently assembling the said frame members which will be securely held in position by the flexible elements 22 and 23 hereinafter described.

The numeral 22 denotes an endless, flexible belt which is mounted in operative engagement with the sheaves 20 on each of the corner members M. The flexible belt 22 is disposed along the rails I0 and II and extends from the sheave 2|] at each I3 denote the side rails 5 upper corner of the frame to the sheave 20 at the opposite lower corner thereof; the said flexible belt 22 thus crosses itself at the center of the frame. The numeral 24 denotes a coil spring which is operatively interposed in the belt 22 to maintain the same in a stretched or taut condition.

The numeral 23 denotes a similar endless belt which is operatively mounted on the sheaves 2| at each corner of the frame to extend along the side portions I2 and I3. The belt 23 extends up wardly from the sheave 2| at each lower corner of the frame to the sheave 2| at the opposite upper corner thereof. The flexible belt 23 is likewise provided with a coil spring -25iwhich is op.-

eratively interposed therein to maintainthe belt in a stretched condition. The forward faces of the rails H and H! are offset rearwardly along the inner marginal portions thereof to provide the longitudinally extending surfaces Na and |2a which are disposed in a plane spaced rearwardly from the plane of the forward face of the frame.

The surfaces Ila and 12a may be provided with graduations or markings 26 and are each provided with a longitudinally extending row of.

spaced curtain engaging pins 21;v Each row of pins 21 extends in parallel, spaced relation to the inner edge of one of the rails H and I2.

The numeral 28 denotes a curtain engaging bar which; extends horizontally across the forward face of the frame withthe end portions thereof overlapping the side rails I2 and I3. One end of the horizontal bar 28 is provided with a bracket 29 which secures the bar to the said rail |2 for sliding movement longitudinally thereof. The bracket 29 projects rearwardly and is provided with a clamp 30 which is operable to secure the same to the portion of the belt 23 extending along the, side rail I2. The rail 28 is provided adjacent the other end thereof with a block'3l which is provided witha clamp-32 which is operable to fixedly secure the adjacent end of-thebar 28 to the portion of the belt extending along the rail The numeral 33- denotesa vertical curtain engaging bar which isprovided atthe lower end thereof with a bracket 34-which is in the form of a channel, in which is received the inner edge of the rail 0 to slidably mount the same thereon.

The bracket 34 is provided-with a clamp-35 which is similar to the clamps 3|! and 32- and which is operable to secure the lower end of the bar 3| to the, portion-of the flexible element 22 extendingalongtherail ID. The vertical bar extends upwardly 'with'the upper end thereof engaging the inner portion of the marginal surface Ila. The vertical curtainengaging bar 33 is provided at the upper end thereof, on the rear face thereof witha-bracket- 36 which-overlaps the rear face of the rail II to slidably mount the same thereon.

The bracket 36 is provided witha clamp 31 for operativelysecuring the upper end of the vertical bar 33' to the portion of the flexible element 22 extending along the rail The horizontal bar 28 is provided alongthe upper edge of the forward face thereof with a rearwardly offset surface 28a and the verticalbar 33 is provided on'the forward face with a similar surface 33a on the side presented toward the rail l2.

Thev surfaces 28a and 33a are similar to the surfaces |2a and Na and each of said surfaces are likewise provided with the graduations 26 It will be seen that each end of the curtain engaging bar 28 is secured to portions of the flexible element 23 which are movable in the same direction and that a movement of one end of said bar will necessitate a similar movement of the other end thereof. Each end of the curtain engaging bar 33 is likewise secured to the portions of the flexible element 22 which are movable in the same direction.

With the frame positioned as shown in Figure 1, one edge of the curtain is secured to the pins 21; on the rail H and one end of the curtain is secured to the pins 21 on the rail I2. The bars 38, and 33 are then moved to the other edges of the curtain and the curtain is secured to the pins 27; on said movable bars.

InFigure 5 there is shown another method of mounting the flexible member 22 on the six sheaves 43a, 38, 39,40, 4| and 62. The flexible member 23 is also shown operatively mounted on six sheaves 43, 44, 45, 46, 41 and 48,. The opposite ends of the curtain engaging bar 32 is suitably secured to portions of the flexible member 22 and the opposite ends of the bar 33 are likewise secured to portions of the flexible member 33 which are movable in the same direction. Other variations of this mounting shown may be used which will produce a like or similar result.

The brackets 29 and 35 are each provided with a locking arm 49 which is hingedly connected thereto and-which is provided at the free end thereof with an eye adapted to receive one of the pins 2? to lock the bars 28 in a fixed position. In the drawings there is shown a bracket 50 which is slidably mounted on the bar 33. The bracket 50 is provided with an ear 5| which projects over the lower portion of the forward face of the bar 28 and is provided with a thumb screw 52' which may be operated to lock the bars 28 and 35 together thus securing both of the bars against sliding movement in the frame.

While I have shown two specific forms of locking means for the bars 28 and 33,,it is to be understood that any suitable locking means may bev employed.

It will be seen that this invention provides a frame which may be packed in a knockeddown condition to occupy a relatively small amountof space in shipment or storage and which can ,be quickly and conveniently assembled to provide a very efiicient device for stretching curtains or other sheet material.

While the invention has been illustrated and described with reference to a particular frame, it is understood that any suitable frame may be employed or the sheaves 25 and 2| mounted on a wall, floor or any suitable supporting structure.

It will also be understood that grommets, eyes, loops or any suitable mechanical equivalent may be employed in place of the sheaves 20 and 2|. The flexible belts 22 and 23 may be in the form of a cord, cable, wire, chain or any suitable flexible element which will suitably function as herein described.

Having thus illustrated my invention and described the same in detail, what I claim as new and desire to secure by Letters Patent is:-

1. In a device of the character described, a rectangular frame having fixed sides, an endless belt mounted for operative movement thereon with portions of the belt extending along opposite sides movable in the same direction, a bar extending across said frame in parallel relation to one side thereof, means to attach the ends of said bar to portions of said belt which are movable in the same direction and curtain engaging means on said bar and the side of the frame disposed in parallel relation to the bar for securing a curtain therebetween.

2. In a device of the character described, a frame having fixed side rails, an endless belt, means to mount said belt for operative movement along opposite sides of said frame, a bar extending between opposite sides of said frame; means to slidably secure each end of said bar to the adjacent side rail of said frame and means to detachably secure the ends of said bar to the portions of said belt which are movable in the same direction; curtain engaging means on said bar and curtain engaging means on a side of said frame which extend in parallel relation to said bar.

3. In a device of the character described, a frame having fixed side rails; an endless belt, means to mount said belt for operative movement along opposite sides of said frame, a bar extending between opposite sides of said frame in parallel relation to the other sides thereof and means to secure the ends of said bar to the portions of said belt which are movable in the same direction, curtain engaging means on said bar and curtain engaging means on a side of said frame which is parallel to said bar.

4. In a device of the character described, a rectangular frame, having sheaves at each corner thereof, an endless belt operatively mounted on said sheaves with like movable portions of said belt extending along opposite sides of said frame, a bar extending across said frame with the ends thereof secured to the like movable portions of said belt, curtain engaging means on said bar and curtain engaging means on the side of the frame positioned opposite said bar.

5. In a stretching device, a support, an endless belt operatively mounted thereon with like movable portions thereof extending along opposite sides of said support, and a curtain engaging bar extending between and secured to said like movable portions of said belt and curtain engaging means along the side of said support positioned opposite said bar.

6. In a stretching device, a support, an endless belt operatively mounted thereon with like movable portions thereof disposed along opposite sides thereof, a curtain engaging bar extending between said like movable portions and operatively secured thereto so as to be movable therebetween and a second belt operatively mounted on said support with like movable portions thereof disposed along the other two sides thereof, a second curtain engaging bar extending between and secured to said like movable portions of said second belt.

'7. In a stretching device, a collapsible rectangular frame, curtain engaging means extending along two adjacent sides thereof, two curtain engaging bars slidably mounted on said frame, said bars disposed at a right angle to each other with each bar opposite one of the sides of said frame which is provided with said curtain engaging means and an endless belt connecting the opposite ends of each bar to restrict the end portions thereof to a like movement and maintain said bars at a right angle to the adjacent portions of said frame.

8. In a stretching device, a supporting structure comprising side rails and end rails, corner members having sockets for receiving the end portions of said rails, said corner members adapted to position said rails in the form of a rectangular frame, sheaves on each corner member, a flexible belt holding said rails in an operative position in said corner members, said belt mounted on said sheaves with like movable portions thereof extending along opposite sides of said frame, a bar extending across said frame with each end thereof connected to one of said like movable portions, means on said bar and on said frame for engaging the article to be stretched.

ARTHUR G. BORNTRAEGER. 

